function checkSub() { 
  if(document.contactform.contact_name.value == "" || document.contactform.contact_name.value == "Ihr Name")
  {
    $.colorbox({width:"50%", inline:true, opacity:"0.30", href:"#err_name"});
    return false;
  }
  
  if(document.contactform.contact_mail.value != "" || document.contactform.contact_mail.value == "Ihre E-Mail-Adresse")
  {
    if(document.contactform.contact_mail.value.indexOf('@') == -1)
      {
	   $.colorbox({width:"50%", inline:true, opacity:"0.30", href:"#err_email_ad"});
       return false;
      }
    if(document.contactform.contact_mail.value.indexOf('.') == -1)
      {
	   $.colorbox({width:"50%", inline:true, opacity:"0.30", href:"#err_email_pt"});
       return false;
      }
    if(document.contactform.contact_mail.value.length < 7)
      {
       $.colorbox({width:"50%", inline:true, opacity:"0.30", href:"#err_email_len"});
       return false;
      }
  } else {
	$.colorbox({width:"50%", inline:true, opacity:"0.30", href:"#err_mail_empty"});
    return false;
  }
    
  if(document.contactform.contact_msg.value == "" || document.contactform.contact_msg.value == "Ihre Nachricht")
  {
    $.colorbox({width:"50%", inline:true, opacity:"0.30", href:"#err_msg_empty"});
    return false;
  }
  document.contactform.msend.value = 1;
  document.contactform.submit();
}